interresting http://www.w3counter.com/globalstats.php
so according to my stats but more on this one :), the winner end user is :
Windows - Internet Explorer - 1024*768
but what about Java version ??
maybe http://kaioa.com/node/40
but I dont really trust those statisitcs… they sounds strange
EDIT: just notice they come from pulp games :), so mmaybe can we have fresher stats 
it may be of interrest here some more stats :
a sample on 3dzzd website :
FPSSample9/index.html 823 => index acces
FPSSample9/FPSSample/FPSSample.3DS 562 => 3ds file loaded (applet run fine)
so as 3DzzD run in almost all platform this give us the following result …
562/823 = 0.68 => 68% of computer can run java 1.1 or higher wich is not a lot 
another sample :
Viewer3D/index.html 3 026
Viewer3D/Viewer3D.class 2 261
Viewer3D/SAMPLE/USINE.3DS 2 012
once again :
2012/3026 => 0.66 => 66%
7%seems to have trouble on downloadin the file (firewall or such)
and a last one :
ROAD8/index.html 626
ROAD8/ROAD/ROAD.3DS 425
ROAD8/Road.class 420
425/626 => 0.68-> 68 %
those are taken from server side but indicate that 68% of user that reach an html with 3DzzD Applet can run it, to be honest I was thinking it was less than that (network problem/java bug) this is finally pretty good results
EDIT:
also probably search engine and hack bot make the result a little worst than the reality